Impaired Dendritic Expression and Plasticity Of H-Channels in the fmr1(-/Y) Mouse Model of Fragile X Syndrome

Despite extensive research into both synaptic and morphological changes, surprisingly little is known about dendritic function in fragile X syndrome (FXS). We found that the dendritic input resistance of CA1 neurons was significantly lower in fmr1(-/y) versus wild-type mice. Consistent with elevated dendritic I-h, voltage sag, rebound, and resonance frequency were significantly higher and temporal summation was lower in the dendrites of fmr1(-/y) mice. Dendritic expression of the h-channel subunit HCN1, but not HCN2, was higher in the CA1 region of fmr1(-/y) mice. Interestingly, whereas mGluR-mediated persistent decreases in Ih occurred in both wildtype and fmr1(-/y) mice, persistent increases in Ih that occurred after LTP induction in wild-type mice were absent in fmr1(-/y) mice. Thus, chronic upregulation of dendritic Ih in conjunction with impairment of homeostatic h-channel plasticity represents a dendritic channelopathy in this model of mental retardation and may provide a mechanism for the cognitive impairment associated with FXS.FRAXAUniversity of Texas Austin Undergraduate Research FellowshipNational Institutes of Health Grant MH048432Center for Learning and Memor

Efficacy and Safety of Lamotrigine in Lennox - Gastaut Syndrome

ObjectiveThe Lennox-Gastaut syndrome (LGS), one of the most difficult epilepsy syndromes to treat, is characterized by a triad of intractable seizures of various types, a slow (< 2.5-hertz) spike-wave pattern in EEG and mental retardation. The aim of this study was to evaluate the efficacy and safety of lamotrigine as add-on therapy in intractable epilepsy of children with LGS.Materials & MethodsIn a quasi- experimental study, 40 children with LGS referred to the pediatric neurology clinic of Shaheed Sadoughi Hospital in Yazd, between August 2007 and to November 2008, were evaluated.ResultsTwenty-two boys and 18 girls with a mean age of 4.12 ±1.8 years were evaluated. At the end of three months of treatment with lamotrigine, 12 % were seizure free, 52% had> 50% reduction in seizure frequency and 12% had increase in seizures. Means of seizure frequency/per week, before and after treatment were 70 (range 1-180) and 18.6 (range 0-60) respectively, indicating effectiveness of the drug in seizure reduction (P value = 0.003). The drug was effective in 72 % of mixed type seizures, 40 % of generalized tonic-clonic and 33% of drop attack and tonic seizures. Transient side effects were seen in 12.5 % (drowsiness in 3 and ataxia in 2 children). No serious side effects were seen.ConclusionLamotrigine should be considered as an add-on therapy in management of intractable epilepsy in LGS

Suppression of turbulence in wall‐bounded flows by high‐frequency spanwise oscillations

The response of wall‐flow turbulence to high‐frequency spanwise oscillations was investigated by direct numerical simulations of a planar channel flow subjected either to an oscillatory spanwise cross‐flow or to the spanwise oscillatory motion of a channel wall. Periods of oscillation, Tosc+=Toscuτ2/ν, ranging from 25 to 500 were studied. For 25≤Tosc+≤200 the turbulent bursting process was suppressed, leading to sustained reductions of 10% to 40% in the turbulent drag and comparable attenuations in all three components of turbulence intensities as well as the turbulent Reynolds shear stress. Oscillations at Tosc+=100 produced the most effective suppression of turbulence. The results were independent of whether the oscillations were generated by a cross‐flow or by the motion of a channel wall. In the latter case, suppression of turbulence was restricted to the oscillating wall while the flow at the other wall remained fully turbulent. Spanwise oscillations may provide a simple and effective method for control of turbulence in wall‐bounded flows.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/71217/2/PFADEB-4-8-1605-1.pd

Control of wall turbulence by high frequency spanwise oscillations

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76966/1/AIAA-1993-3282-205.pd

Spatial variability and estimation of tree attributes in a plantation forest in the Caspian region of Iran using geostatistical analysis

This research was conducted to investigate spatial variability and estimate tree attributes in a plantation forest in the Caspian region of Iran using geostatistical analysis. Sampling was performed based on a 50m?125m systematic grid in a maple stand (Acer velutinum Boiss) 18 years of age using circular samples of 200m2 area. Totally, 96 sample plots were measured in 63 hectares and 14.25 hectare was inventoried as full census area. Experimental variograms for forest stem basal area, stem density and tree height attributes were calculated and plotted using the geo-referenced inventory plots. The calculated variograms of basal area and height showed a high spatial auto-correlation, which is fitted by spherical model. However, stem density showed a large nugget effect. Estimations for basal area and height interpolated by ordinary block kriging and cross validation results showed that all the estimations were accurate. Furthermore, the estimated kriged mean of basal area showed no significant difference to the real mean in the full census area. Therefore, geostatistical analysis is able to capture and explain the spatial variability as well as estimate tree attributes (not stem density) in this kind of plantation forest, accurately

Spatial variability of forest growing stock using geostatistics in the Caspian region of Iran

Estimating the amount of variation due to spatial dependence at different scales provides a basis for designing effective experiments. Accurate knowledge of spatial structures is needed to inform silvicultural guidelines and management decisions for long term sustainability of forests. Furthermore, geostatistics is a useful tool to describe and draw map the spatial variability and estimation of forest variables. Therefore, this research was conducted to investigate on spatial variability and to estimate forest stock variables using geostatistical approach in a mixed hardwood forest, located in the Caspian region of Iran. Field sampling was performed based on a 150m by 200m systematic rectangular grid of 3 clustered plots (50m away). Each sample plot consisted of two concentric circles. Overall, 434 sample plots were measured in 502 hectares. Experimental variograms for forest basal area, volume and tree density were calculated and plotted using the geo- referenced inventory plots. All the variograms showed weak spatial auto- correlations between samples, even in short distances. Estimations were made using fitted variogram models and ordinary block kriging. Cross- validation results showed that all the estimations are biased, because of the large variability and weak spatial structure in the forest stock variables. Therefore, kriging could not make accurate estimations because of high spatial variability of forest growing stock related variables in this heterogeneous and uneven-aged forest

Group Meritocratic Fairness in Linear Contextual Bandits

We study the linear contextual bandit problem where an agent has to select one candidate from a pool and each candidate belongs to a sensitive group. In this setting, candidates⧠rewards may not be directly comparable between groups, for example when the agent is an employer hiring candidates from different ethnic groups and some groups have a lower reward due to discriminatory bias and/or social injustice. We propose a notion of fairness that states that the agent* policy is fair when it selects a candidate with highest relative rank, which measures how good the reward is when compared to candidates from the same group. This is a very strong notion of fairness, since the relative rank is not directly observed by the agent and depends on the underlying reward model and on the distribution of rewards. Thus we study the problem of learning a policy which approximates a fair policy under the condition that the contexts are independent between groups and the distribution of rewards of each group is absolutely continuous. In particular, we design a greedy policy which at each round constructs a ridge regression estimate from the observed context-reward pairs, and then computes an estimate of the relative rank of each candidate using the empirical cumulative distribution function. We prove that, despite its simplicity and the lack of an initial exploration phase, the greedy policy achieves, up to log factors and with high probability, a fair pseudo-regret of order √dT after T rounds, where d is the dimension of the context vectors. The policy also satisfies demographic parity at each round when averaged over all possible information available before the selection. Finally, we use simulated settings and experiments on the US census data to show that our policy achieves sub-linear fair pseudo-regret also in practice

Surface Electromyography Feature Extraction Based on Wavelet Transform

Considering the vast variety of EMG signal applications such as rehabilitation of people suffering from some mobility limitations, scientists have done much research on EMG control system. In this regard, feature extraction of EMG signal has been highly valued as a significant technique to extract the desired information of EMG signal and remove unnecessary parts. In this study, Wavelet Transform (WT) has been applied as the main technique to extract Surface EMG (SEMG) features because WT is consistent with the nature of EMG as a nonstationary signal. Furthermore, two evaluation criteria, namely, RES index (the ratio of a Euclidean distance to a standard deviation) and scatter plot are recruited to investigate the efficiency of wavelet feature extraction. The results illustrated an improvement in class separability of hand movements in feature space. Accordingly, it has been shown that only the SEMG features extracted from first and second level of WT decomposition by second order of Daubechies family (db2) yielded the best class separability